Many office and writing products, food packaging etc are manufactured from plastic or metal or combinations of these materials. With the increase in environmental awareness over a number of years, there is a desire to be able to use instead renewable raw material containing for example cellulose, such as cardboard and paper, for example in pens, sleeves for glue sticks, containers for correction fluid, sleeves for various foodstuffs etc. One problem, however, is that cardboard absorbs and/or lets through liquid if it is not protected against the liquid or treated in a suitable manner. It is relatively common to provide pens for example with an outer sleeve of cardboard, in which however the inner ink container is still of plastic or metal. To the eye this perhaps appears to be environmentally friendly, but is not so in practice. Other attempts have been made to utilize cardboard or paper by coating a sheet of paper with a liquid-proofing plastic layer, the sheet then being wound round several turns in the form of a sleeve, so that a cylindrical space is formed. A disadvantage of this method is that the material in the sleeve becomes impossible to recycle. It would in fact also be possible to dip a cardboard tube into a fluid, which on drying/solidifying produced a liquid-proofing film. The problem then is that it is difficult to apply text and other print to the outside of the sleeve. As far as the inventor knows, no method has been developed for the manufacture of cardboard sleeves or similar items which are coated on the inside only with a liquid-proofing film of a type other than plastic.